A. Field of the Invention
This invention relates to a lawn or leaf rake, more particularly to a rake which can be cleaned of leaves which become lodged on the tines during the raking process, by operation of an integral actuating handle without the need for shifting of the operator's hands from the position customarily used in raking. The invention embodies significant improvements in simplicity of design and economy of construction over the existing state of the art of self cleaning rakes.
B. Description of the Prior Art
The art of self-cleaning rakes is documented from the early years of the U.S. Patent Office. However, prior to the most recent patents, "Hand rakes with cleaner", that is prior to U.S. Pat. No. 2,705,394, practically all of the prior patents pertain to garden rakes, those with rigid tines set at right angles to the handle, as differentiated from lawn or broom rakes with flexible tines, which are generally longer, more slender, and in the same general plane as that of the rake handle.
This flexible aspect of the lawn rake tines presents additional and unique circumstances which must be addressed in the design of a self cleaning apparatus for such rakes. These circumstances are further compounded by the predominant radial tine placement or fan shape of most broom rakes and the convention of including a downward bent section at the end of each tine to enhance leaf gathering efficiency.
U.S. Pat. Nos. 3,884,023 and 4,850,185, in addition to one other recent patent for self-cleaning leaf rake, U.S. Pat. No. 4,776,158, address these problems in different ways. All three accept the existence of the downward angled tines, and their arts embody means of dealing with the problem of moving a cleaning device past the angled crooks to reach the very end of the tines in order to effect thorough removal of lodged debris. The instant invention substitutes gradually downward arcing tines of flexible material to enhance the leaf gathering capacity of the rake normally accomplished by the angled ends of most tines. The existence of a gradual arc as opposed to an abrupt crook in the tines allows a simpler cleaning device to be moved along the tines in conjunction with a more direct actuating mechanism.
U.S. Pat. No. 3,884,023 utilizes a cleaning apparatus with actuating linkage (including handle) involving 7 sections or parts comprising at least 10 separate pieces plus fasteners. The apparatus as taught involves an estimated 11 steps in the assembly of the separate pieces, (not including the tine/head subassembly), in addition to special preparation of the handle with a groove to accept the actuating linkage. The construction of the tines and tine head assembly is not taught in full detail.
U.S. Pat. No. 4,776,158 is not of fan or radial shape tine placement, as is the instant invention, having instead a rectangular shape with parallel tines. Such shape tends to be less manageable in some raking circumstances than the more customary fan shape. This patent and U.S. Pat. No. 4,850,185 is otherwise distinguished from the instant invention by the existence of a separate handle for the actuating mechanism requiring release of the down side hand of the operator from its customary position on the rake handle during raking in order to grasp the actuator handle to effect cleaning. With the instant invention, it is not necessary to release or reposition the hand in order to effect cleaning.
U.S. Pat. No. 4,850,185 maintains a stationery cleaning apparatus attached to the handle and effects removal of debris by withdrawing the tine assembly into the cleaner by an actuator linkage attached to a lever handle. Other than the tine/head subassembly, which is not taught in detail, there are 8 pieces plus fasteners in the handle/cleaner and actuating linkage, including the tension spring and tine spreader, which require an estimated 9 assembly steps.
In addition to rakes classified as self cleaning, there are a number of patents that relate to adjustable, collapsible, or retractable rakes. These are of a broom or lawn rake variety and have similarities of mechanism with this and some of the prior self cleaning rake inventions. U.S. Pat. No. 2,149,429 includes a guide bar that moves to the distal end of the rake tines. It does not, however, move to the very end of the crooked tines, as does the mechanism in U.S. Pat. No. 3,884,023 or in the instant rake, making it ineffective in cleaning. The same lack of movement to the very ends of the tines makes the adjustable or collapsible rakes taught in U.S. Pat. Nos. 3,727,389, 3,701,243, and 4,901,515 ineffective in cleaning. In addition, all four of the above incorporate a catch or locking mechanism which must be operated in order to move the spreader bar along the tines. This intervening mechanism is not required in U.S. Pat. No. 3,884,203 or in the instant invention.
U.S. Pat. No. 4,236,742 relates to a retractable rake for use as a portable golf rake or for light raking chores. This rake has a hollow shaft, flared into a rake head at one end to enable a plurality of tines to be retracted into the head. The tines are locked into position in both their open and retracted position, by means of a leaf spring and button arrangement, thus requiring operation of the button in order to retract the tines. This invention, as taught, is not designed for general lawn usage. In addition, the rake does not incorporate as economical a use of materials or ease of manufacture or use as does the instant invention.
The lack of wide spread commercialization of existing designs for a function whose utility is readily recognized by anyone familiar with leaf raking suggests the restrictive manufacturing costs and/or lack of operational ease of use and effectiveness of the existing designs. The instant invention utilizes a cleaning apparatus with actuating linkage (including handle) involving 4 sections or parts comprising 4 separate pieces plus fasteners, in its spring steel version and 2 parts comprising 2 separate pieces, in its molded plastic version. Manufacturing steps are necessarily reduced in both cases, with an estimated 5 steps for the spring steel version and 3 steps for the molded plastic version. Operation of the cleaning mechanism requires only one small movement of the operator's lower arm, pivoting at the elbow, without appreciable disruption of the raking rhythm.